Plug



FIG. 1 is a front elevational view of the design;

FIG. 2 is a left side elevational view of the plug in FIG. 1;

FIG. 3 is a top plan view of the plug in FIG. 1;

FIG. 4 is a bottom plan view of the plug in FIG. 1; and,

FIG. 5 is a perspective view of the plug in FIG. 1. 

The ornamental design for a plug, as shown and described. 